Indoor cultivation of fruits, vegetables, flowers and ornamental plants is an increasingly popular method of producing living plants, whether for the horticulturist, hobbyist or professional nursery operator. Hydroponic plant growth systems have been introduced which typically use an open-topped outer container for holding a liquid combination of water and plant growing nutrients and an open-topped inner container for holding an inert growing medium. Plant roots are grown in the medium. The inner container includes openings at its lower end to allow liquid to enter the growing medium and to drain from it. Automatic systems, generally requiring submersible pumps and hydraulic pumping systems, maintain the correct amount of growing nutrient. The inert growing medium typically includes clay pellets, sand, gravel, perlite, vermiculite, or the like. Alternately, in more complex and difficult to control aeroponic applications, plant roots are suspended in air and are fed constantly with a nutrient-rich mist.
During hydroponic growing, it is important that the delivery of the liquid nutrients to plant roots not exceed a maximum level, nor should the plant roots be deprived of nutrient and allowed to dry for too long a period of time. If over-watering occurs, the plant may die or have its growth inhibited from root rot. Allowing the roots of the plant to be dry for too long results in dehydration and starving the plant. Thus, an accurate method of delivering controlled amounts of liquid nutrient to the roots of a plant within a planter is desirable since it has been discovered that plant growth may be enhanced if periods of root saturation are followed by periods of root dryness.
Furthermore, to control the expenses of nutrient supply to plant roots and minimize the effort in re-cycling nutrient, it is advantageous to concentrate the nutrient delivery only within the area of root growth as opposed to spreading nutrient over a larger area encompassing areas not having root growth activity. Known nutrient supply systems do not have the commercial advantages of the combination of these provisions as provided by the present invention.
Hydroponic systems provided by the present invention may be used by commercial growers to control and deliver specific doses of moisture and nutrients so that herbs, in particular, have optimum flavor and consumer appeal. Hydroponically grown herbs, including basil, tarragon, arugula, mint, chilies, and the like, are therefore, excellent candidates as the commercial demand for such herbs is strong throughout the years, independent of growing season. However, since the taste of a plant is determined by the elements absorbed through its leaves and roots, it is desirable that such edible plants be produced in sheltered or enclosed environments free of pesticides, herbicides and artificial fertilizers. The expense of producing and maintaining a enclosed environment is impacted significantly by the space required within a hydroponic growing system. There is thus a further need for compact plant growth systems so that a relatively high plant growth density within a sheltered environment may be obtained.
U.S. Pat. No. 4,965,962 discloses a hydroponic culture system comprising angle panels having holes for supporting plants with roots projecting through the holes, and a hydroponic solution spraying mechanism. A plant cultivation structure made from angle panels in rows, the top edges of adjacent angle panel rows connected with canopies to form substantially triangular-sectioned spaces between the adjacent angle panel rows.
U.S. Pat. No. 5,557,885 discloses a hydroponic planter having a tank storing the mixture of water and nutrients and a sight glass for gauging the proper water level range. Compressed air is used to draw water into the bottom of the tube and lift it to the top of the tube where it is discharged into a planted pot. Water and nutrient solution trickles down through an inert growing medium and drains from the bottom of the pot back into the storage tank.
U.S. Pat. No. 5,168,664 discloses a hydroponic planter having an outer container and an inner liner. The liner includes a central inverted cup-shaped reservoir for a liquid nutrient solution. The outer wall of the liner includes slots extending substantially above the height of the reservoir, to provide aeration of the roots of plants growing in the planter. A liquid level indicator shows when to add nutrient solution to the planter, and indicates when too little, sufficient or too much nutrient solution has been added.
U.S. Pat. No. 4,965,962 discloses a hydroponic planter having angle panel members with holes for supporting plants with roots projecting through the holes. A hydroponic solution spraying mechanism is moveable along the longitudinal direction of the panels. The spraying system provides a uniform spraying over the entire insides of the panels and not concentrated in the plant rooting areas.
U.S. Pat. No. 4,753,036 discloses a hydroponic planter having an upper surface with an opening for a plant, and a side surface having a opening to pass the rootstock of the plant. Each of the planters receives predetermined amounts of water and porosity grain fillers, such as foaming brick stones, and plants are set throughout or in part of the planters.
U.S. Pat. No. 4,704,818 discloses a hydroponic planter having frustoconical shell-like members with openings in the walls through which plants grow. A matrix of water permeable material is provided throughout each shell like member into which the plants are inserted. Liquid nutrient is introduced near the top of the rooting matrix so that with this design, nutrient is spread throughout the matrix and not concentrated in the plant rooting areas.
U.S. Pat. No. 4,419,842 discloses a hydroponic planter having a closed lower chamber for receiving a liquid nutrient solution and a top open-ended upper chamber for receiving filler material and the desired plant. A nutrient supply pipe extends downwardly into the lower chamber so that nutrient solution may be fed in a continuous cycle from the lower chamber to the upper chamber and back again.
Some of the above described operations generally use large amounts of floor space per single plant, thereby requiring expensive efforts to provide a large controlled environment free of pesticides, herbicides, etc., suitable for use in a commercial hydroponic growing operation. To minimize over- and under-watering, various gauges and carefully controlled watering or spraying devices have been developed. These systems fail to concentrate the nutrient supply in the plant rooting area and generally provide a nutrient supply in a uniform pattern over an entire plant growing area, creating either waste or the need to re-cycle an inordinate amount of nutrient.
In view of the foregoing, it is therefore believed to be advantageous to provide a hydroponic growing station having a simple nutrient delivery system having a concentrated nutrient delivery system in a compact design allowing for a cost-effective enclosed plant growing environment. An important improvement over the art provides nutrient only near plant roots thereby optimizing growing efficiencies, so that herbs, in particular, may be delivered to consumers without excessive costs. A further need within the industry is the ability to provide an optimum amount of growing illumination for different plant species, without the wastes of overlapping or non-illuminated areas.